1. Field of the Invention
This invention relates generally to weighing apparatus and particularly to portable, low profile weighing scales. The weighing scale provided by this invention is useful for weighing private, commercial and military aircraft efficiently, reliably and accurately.
2. Background Information
Applicants Kroll et al. disclosed scales in U.S. Pat. Nos. 4,714,121, 4,979,581, and 5,232,964, and load cells in U.S. Pat. Nos. 4,775,018, 4,813,504, and 5,228,527. These scales and associated load cells were designed primarily for weighing land vehicles, such as high performance race cars, and large trucks. The scales and load cells handle a broad range of weights and have varying degrees of accuracy. Additionally, the scales have varied designs in terms of height, weight, portability and method of use. A common design factor shared by all of these scales and load cells is that in each, the mounting of the load cell in and to the scale is unique and provides a significant advantage over the prior art.
The weighing scale assemblies and load cell structures of the present invention are particularly useful for weighing a variety of sizes and types of private, commercial and military aircraft. Total weighs of such aircraft can exceed 1,000,000 lb., as for example in the case of a fully loaded Boeing 747. The required capacity of each scale or weighing pad is in the range of 10,000-60,000 lb. The accuracy of these weighing scales is plus or minus 0.1 percent. These criteria and the particulars of the use environment demand specific mechanical structures for scales, especially the scale platform and the mounting of the load cells to the platform and the remaining elements of the scale.
It is an object of this invention to provide a weighing scale that may be used to weigh aircraft. A further object of this invention is to provide a weighing scale that is extremely strong and yields highly accurate repeatable weighing results. It is a particular object of this invention to provide a scale that has an improved platform member and an improved mechanical structure for mounting one or more load cells to the platform and to a base member. Although the need for a strong, reliable and highly accurate weighing scale such as that provided by the present invention has long existed in the private, commercial and military aircraft industries, none insofar as is known has been proposed or developed.